Fuel injection pump



Nov. 14, 1944. I H Q HAL 2,362,822

FUEL INJECTION PUMP Original Filed June 22, 1940 2 Sheets-Sheet l FI B1 1.

Patented'Nov. 14,1944

FUEL mmc'rron rum Jesse E. Houser, William A. Hancock, and Lewis T. Rowe, Dayton, Ohio, assignors to The Dayton Liquid Meter 00., Dayton, Ohio, a corporation of Ohio Original application June 22, 1940-,'Serial No. 341,840. Divided and this application May 9,

1941, Serial No. 392,696

12 Claims. (01. 299-1012) The present invention relates to an injection pump drip preventing means for use with an injection device for high speed engines. The problems to be encountered in devices of this type v have been fully described in ourapplication Ser.

2,301,407, of which the present application is a division.

An object of the invention, herefore, is to provide an improved drip preventing means for fuel injection pumps.

Other objects will appear hereinafter. Inthe drawings: V Figure 1 represents a diagrammatic view of a typical engine provided with the improved injector pump for controlling the flow of fuel to the respective cylinder.

Figure 2 is a sectional view, partly in elevation,

of the improved pump together with the additional feature by which dripping at the'injector,

nozzle is prevented.

Figure 3 is a fragmentary view of a form of fuel nozzle which cooperates with certain structural features of the present invention.

Figures 4 and5 are enlarged detail views of the check valves employed in the suction and injection lines of the improved pump; These fig-.

ures show in'magnifled form the construction of the improved injector pump above the injection diaphragm.

Referring more particularly to Figure 1, thenumeral I generallyidesignates a typical form of automotive engine as specifically having six cylinders, as indicated by the six spark plugs 2. The engine block is indicated at 3 and the bed at 4. Only the left-hand cylinder has been shown 'in detail and this cylinder contains a piston 5.

' No. 341,840, filed June 22, 1940, now Patent No.

The'bed of the engine isprovided with a flange 6, and on this flange rests as many injector pumps of the improved type as there are cylinders, these pumps being preferably secured to the engine and positioned directly below the respective cylinders.

The parts of the improved injector pumps are contained within a casing 1, which may be of a general cylindrical form, and from the upper portions of eachcasing there is a fuel intake line 8 which connects through a common pipe 9 to a casing 1, the upper .pipe H servingas anoil inlet pipe and the lower pipe 12 serving. as an oil outlet pipe, the circuit being completed through'a combined oil reservoir and, filter ll 3.

The details of the improved injector pump are illustrated in Figure 2. It willbenoted that the casing 1 is actually constitutedof two members, joined together by screws |4. The upper casing I6 is provided with multi-shouldered portions ll, l8, thelatter'terminating in. a screw'threaded 'member l9, to which the pipe. I0 is secured by There is a, cylindrical openingv 2| passing down through the any suitable form of coupling 20.

casing l6 and in line with the opening in thedischarge pipe l0.

This opening 2| has the same diameter down as far as the shoulder 22 (Figure 4-), 'andthe opening emerges into another openingof smaller, diameter, as indicated at 23. At the lower part of the opening 2| and resting on the shoulder 22 there is'a hollow thimble member 24 (Figure 4) which has a transverse portion 25 containing two diagonally directed openings 26, A pinji projects downwardly from the transverseportion a or web 25, this .pin being in line with a ball 28, which in cooperation with opening 29 at the bottom of the thimble constitutes a check valve. It will be apparent that the pin 21 merely serves to limit the upward movement of the ball when pressure is applied to the fuel passing through the thimble 24. The upper casing I6 is also provided with a transversely extending opening 30, which contains'a sleeve 3| having a centrally aligned aperture 32. Theball 33, forming part of a second check valve, is urged by the spring 34 against the left-hand end (Figure 4) of the opening 32. There is a projection at 35 extending to the right (Figure 2) 0f the casing l6, this projection bein threaded to receive a coupling 36 for securing the fuel inlet pipe 8 to the casing in line with the opening 30.

The casing I6 is provided at its lower end with a countersunk conically shaped opening 31, this Qpeningbeing adapted to receive a diaphragm 38, preferably of 'a steel composition which resists corrosion by all of the known types of fuel. This diaphragm may have any desired thickness, but we have found that it performs particularly well when having a thickness less than of an inch. The diaphragm is seated between an annular rim portion formed on the casing l6 and the upper surface of a lower casing 39 of the fuel injector pump, whicri'"together contain the main parts .of theinjector pump.

The lower casing 39 contains me injector-pump particularly described and claimed in our aforesaid patent. This pump and its associated parts include the cylinder 4|, cylinder bore 42, plunger forth in our patent and relate to-the pump foractuating the diaphragm 38.

The nozzles which are attached to the cylinder end of the discharge pipes I are shown in Fig-' ure 3. This nozzle may conform to any of the well known types on the market which produce a spray injection and are provided with a spring tension cap for closing off the nozzle'when the fluid pressure therein becomes'less than the predetermined amount. The preferred form of nozzle is illustrated in Figure 3, and consists of a hollow cylinder 92 having a rounded portion 93 projecting from one side and screw threaded to receive a coupling 94 for securing the pipe I0 to the projection 93. The projection 93 contains a bore 95 which communicates with a bore 99 within the cylinder 92. v i

The, bore 991s. reduced to a small bore indicated at 91, which receives an arcuate headed pin 98. The upper surface of the head 99 of the pin; seats against the lowermost surface of an enlarged portion I00 of the cylinder 92. The latter is threaded, as indicated at IOI, into a threaded opening formed in the cylinder head I02. The pin 90 has four or more longitudinal grooves I03 extending along its length, and communicating at-"one end with the bore or opening 9.6 andat the other end with an annular opening I04 formed at the lower end of the enlarged cylinder portion I00. The pin 99 has a threaded opening I05 in its upper end which receives'the threaded shank of a rod I06 contained within the opening or bore 99. The rod is.provided. with an enlarged head I01. A cap I08 is threaded to the exterior surface of the cylinder 92.. There is a compression spring I09 loosely su rounding the rod I09 and which bears at its upper end against the head I01, and at the opposite end against the cylinder portion I00.

The purpose of this spring is to resiliently hold the head 99 of the pin 98 against its'seat, thereby preventing fuel from flowing beyond the an nular. space I04 except when the fuel-is under high pressure.

The pressure produced by the plunger on the trapped oil serves to flex the diaphragm 38, as shown in Figure 4, causing a reduction in the The plunger has an cams 89 and fuel injection pumps as there are cylinders, as indicated in Figure 1, and the cams are so positioned with respect to the cam shaft 69 (Figure 2) as to cause the circular spray to leave the respective nozzles in proper timed relation, depending on the firing order of the engine cylinders. The non-drip device is, in combination with the other claimed features, a principal object of the present invention and permits the nozzle to completely shut off fuel at the termination 01 the charge provided by the flexed diaphragm 39.

I During the flexing of the diaphragm by the oil under pressure, the fuel is transmitted under pressure through the pipe [0, into the annular opening I04, from which it is ejected as a spray of circular configuration. At the moment the pressure exerted on the fuel starts to recede, due to the return of the diaphragm to its unfiexed position, the head 99 is withdrawn upwardly by the spring I09 to snap the nozzle closed. It is apparent from the design of the nozzle structure,

' particularly from a consideration of the differential areas involved, that only a relatively small pressure may be permitted to remain within the nozzle structure during the closing period. If the pressure in the fluid is not reduced at a rate to correspond with the closing snap action, dripping will inevitably take place from the end of the nozzle. This after-drip enters the engine cylinder at a time later than the main injection impulse, and represents waste since it is not withdrawn into the engine cylinder at the suction valve. It will be understood that only a few drippings when multiplied by the number of cylinders, and being repeated many times per minute volume of the space directly above the diaphragm.

This, in turn, produces a large increase in pressure on the fuel'trapped above the diaphragm, causing the ball 33 to be flrmly seated against its sleeve 3|, thereby closing oif the inlet passage 32 and also forcing the ball 23 in the discharge passageway to be moved away from the opening 29. Fuel under pressure is therefore caused to pass upwardly through the passageways 23, 29, through the diagonal passageways 29, into the respective pipes I 0 which lead to the cylinders of the engine. From the pipe I0 (Figure 11) the fuel is caused to pass under extremely high pressure through the bores 95, 90, through the grooves 91, into the annular space I04, forcing the head to be moved downwardly (as seen in the figure) away from its seat, and permitting the fuel under high pressure to be ejected as a spray of circular configuration about the entire under side of. the head 99, into the cylinder of the engine.

It will be understood that there are as many in the case of high speed engines, may produce considerable waste. In accordance with the present-invention we have provided a feature which cooperates extremely satisfactorily with our improved injector pump, and completely eliminates the dripping of fuel.

Referring to Figure 2, the casing I6 is provided with a diagonal opening III which communicates at one end with the discharge opening 2| and at the other end with an annular opening II2 formed in a small cylindrical plug II3. This plug is provided with a combined diagonally and longitudinally extending opening I I4, which communicates at one end with the annular opening I I2 and at the other end terminates at the lower surface of the .plug. There is a, diaphragm H5, preferably of thin flexible metal and non-corrosive with respect to the fuel, secured to the lower surface of the plug. For practical reasons this diaphragm is welded to a sleeve I I6, and the latter is secured to the plug H3. The plug is so positioned within the casing I6 as to permit a free flexing movement of the diaphragm I I5, only in a. half cycle. In order to remove the plug when necessary a downwardly extending hole Ill may b provided in the casing, directly in line with the plug, and this hole is closed by a screw II8.

Now assume that the nozzle (Figure 3) is in the act of closing, after having ejected a full charge of fuel into one of the cylinders, so that the head 99 is snapped upwardly. 'In the un improved form of nozzle, the back pressure may remain high or fail to reduce sufficiently quickly and cause dripping of fuel. In accordance with our invention, this excess pressure is relieved by the flexing of the diaphragm II5 (Figure 5) which permits the column of trapped fuel to expand, thereby lowering the pressure and perstroke, means for preventing drip at theinjec-v mitting the head 99 to seat promptly. Figure 2- to its initial fiat position. In Figure 4 the-diam 5 phragm H5; is in its seated position, i; e., unexi tended, because the main diaphragm 38 is, in. the act of causing the ejection of fuel at the nozzle, and no backpressure has been built up because the head 99 is maintainedin its open po mined movement ofthe piston on its dischargeq stroke, means for preventing drip at the injection:

device, said drip; preventing means including a diaphragm, av compartment on either sidepf said.

sition by the pressure in the fuel.q

It will "be noted that the non-drip feature described immediately above cooperates with trims improved injector pumpin such a way. as rte-prevent any dripping from the nozzle after the i5. m u t s pectively with the inlet and. metered charge of fuel has been ejectedjatthe nozzle due to the flexing of the main. diaphragm 38. Consequently, theoperationi of,- the latter serves accurately to measure the fuel contentv of each-charge and to cause the full charge tob s .10

' we claim as new and desire tolse'cure by Letters Patent is: r

1.In a'fuel injection pumping means for use with an injection device, said pumping means 130 having a piston, a dischargev check valve, and means for relieving pressure between the piston and saiddischarge check valve after a predeteremined movement of the'pist on on its'discharg'e tion device, said drip preventing means'include ing a diaphragm having its sides communicating respectively with the inlet and outlet sides of the check valve.

2. In a fuel injection pumping means for use with an injection device, said pumping means having a'piston, a'discharge check valve and means for relieving pressure between the piston and'said discharge check valve after a predetermined movement of the piston on its discharge stroke, means for preventing drip at the injection device, said drip preventing means includingv a diaphragm having its sides communicating respectively with the inletand outlet sides of the check valve, one of said chambers being formed by a bore and a removable plug therein.

,3. In a fuel injection pumping means for use with an injection device, said pumping means and said discharge check valve after a predetermined movement of the'piston on its discharge stroke, means for preventing dripat the injecaplurality of compartments communicatingwith the inlet-andoutlet sides. ofthe check valve and a diaphragm separating said compartments.

5. In a fuel injection pumping; means for use I with an injection device, said pumping means having a piston, a discharge check valve and means for relieving pressure between the piston andsaid discharge checkvalve after a predeterdiaphragm, each compartment having .means1 outlet sidesof the check valve, saidcompartments means for relieving pressure between the piston and said" discharge, check valve after a predetermined movement of the: piston on its discharge,

troke, means for preventing drip at the injection device, said drip, preventing means including a. diaphragm, an; elongated chamber on each side oflsaid diaphragm, and passageways communicating respectively with the inlet and outlet sides ofthe check valve and'said chambers.

with' an injection device, said pumping means having apiston, a discharge check. valve and.

means, for relieving pressurebetween thepi ston and said discharge check valve after a predeter- Y mined movement of the piston onj its discharge stroke, means for preventing drip at the injec- 7 tion device, said-drip preventing meansincluding adrip diaphragm having its sides communi eating respectively withthe inlet and; outlet sides All. of, the check valve, and "a pump diaphragm one 1 side of'whi'chisincommunication with-said piston and the other side of which is in communication with that side'of the drip diaphragm which 7 communicates with-the inlet side of said check -15 valve, the operation of said piston and said injection device causing said diaphragms to be alternately flexed and depressed.

8. In a fuel injection pumping means for use with an injection device, said pumping means having a piston, a discharge check valve and means for relieving pressure between the piston and said discharge check valve'after a prede-s termined movement of the piston on its discharge stroke, means for preventing drip at the having a'piston, a discharge check valve and m-ecti n r means for relieving pressure between the piston J 0 device Said drip preventmg means in cludinga drip diaphragm having its sides communicating respectively with the inlet and outtion device, said drip preventing means include no plug therein a pump, diaphragm one Side ing an expansion compartment having a dia phragm with its sides communicating respectively 7 with the inlet and outlet sides of the check valve whereby when excess pressure occurs in the fuel of which is in communication with said piston and the other side of which is in communication with that side of the drip diaphragm which communicates with the inlet side ofsaid check valve,

after the injection device has closed, a portion the operation f Said piston and said injection of said fuel is permitted to enter said expansion chamber in order to relieve the excess pressure in said injection device.- I

4. In a fuel injection pumping means for use device causing said diaphragms to be alternatel flexed and depressed. A

9. In a fuel injection pumping means for -use with an injection device, said pumping means with an je tio ce. said pu pi means having a piston, a discharge check valve and having a piston, a discharge check valve and means for relieving pressure between the piston and said dischargecheck valve after a predetermined movement of the piston on its discharge means for relieving pressure between the piston and said discharge check valv after a predetermined movement of the piston on its discharge stroke, means for preventing drip at the injecstroke, means for preventine drip at h inl'9 tion device, said drip preventing means includhaving a. piston, a discharge check valve and.

7. In a fuel injection pumping, means for use.

ing an expansion compartment having a drip diaphragm with its sides communicating respectively with the inlet and outlet sides oi the check valve whereby when excess pressure occurs in the fuel after the injection device has closed, a portion of said fuel is permitted to enter said expansion chamber in order to relieve the excess pressure in said injection device, and a pump diaphragm one side of which is in communication with said piston and the other side of which is in communication with that side of the drip diaphragm which communicates with the inlet side of said check valve, the operation of said piston and said injection device causing said diaphragms to be alternately flexed and depressed.

10. In a fuel injection pumping means for use with an *injection device, said pumping means having a piston, a discharge check valve and means for relieving pressure between the piston and said discharge check valve after a predetermined movement of the piston on its discharge stroke, means for preventing drip at the injection device, said drip preventing means including a plurality of compartments communicating with the inlet and outlet sidesof the check valve and a drip diaphragm separating said compartments, and a pump diaphragm one Side of which is in communication with said piston and the other side of which is in communication with that side of the drip diaphragm which communicates with the inlet side 01' said check valve, the

mined movement of the piston on its discharge stroke, means for preventing drip at the injection device, said drip preventing means including a drip diaphragm, a compartment on either side of said drip diaphragm, each compartment having means communicating respectively with the inlet and outlet sides of the check valve, said compartments being out of alignment with each other, and a pump diaphragm one side of which is in communication with said piston and the other side of which is in communication with that side of the drip diaphragm which communicates with the inlet side oi! said check valve, the operation of said piston and said injection device causing said diaphragms to be alternately flexed and depressed.

12. In aiuel injection pumping means for use with an injection device, said pumping means having a piston, a discharge check Valve and operation of said piston and said injection demeans for relieving pressure between the piston and said discharge check valve after a predetermined movement of the piston on its discharge stroke, means for preventing drip at. the injection device, said drip preventing means including a drip diaphragm, an elongated chamber on each side of said drip diaphragm, passageways communicating respectively with the inlet and outlet sides of the check valve and said chambers, and a pump diaphragm one side of which is in communication with said piston and the other side of which is incommunication with that side of the drip diaphragm which communicates with the inlet side of said check valve, the operation of said piston and said injection-device causing said diaphragms to be alternately flexed and depressed.

, JESSE E. HOUSER.

WILLIAM A. HANCOCK. LEWIS T. ROWE. 

